KR20220001458A - MODIFIED SINTERED Nd-Fe-B MAGNET, AND PREPARATION METHOD AND USE THEREOF - Google Patents

Abstract

The present invention relates to a modified sintered neodymium-iron-boron magnet and a manufacturing and application method thereof. The modified sintered neodymium-iron-boron magnet is manufactured through the progress of grain boundary diffusion on a base material, the base material is a sintered neodymium-iron-boron magnet, and a grain boundary diffusion source comprises a first diffusion source and a second diffusion source, wherein the first diffusion source is a PrMx alloy, and the M is at least one selected from among Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb, Mn, Co, Fe, Ti, Cr, Zr, Mo and Ge, and the second diffusion source is a heavy rare earth Dy and/or Tb. A low-melting point alloy including Pr is used to be preferentially led into the magnet to form a wider and longer diffusion passage, and then, the passage is used as a high-speed diffusion passage for heavy rare earth elements, thereby accelerating an improvement in the depth and speed of the diffusion of the heavy rare earth elements as well as a coercive force.

Description

Modified sintered neodymium-iron-boron magnet and manufacturing method and application thereof

The present invention relates to a modified sintered neodymium-iron-boron magnet and its manufacturing method and application, and belongs to the field of rare earth permanent magnet material technology.

Sintered neodymium-iron-boron magnets are widely applied in fields such as wind power generation, energy-saving home appliances and renewable energy vehicles based on their excellent overall magnet performance. In addition, with the continuous advancement of manufacturing technology and the improvement of people's awareness of environmental protection, the market is attracting attention in three fields: energy saving and environmental protection, new and renewable energy, and new and renewable energy automobiles, and the capacity is 10 to 20 every year. It is growing rapidly at a rate of % and has excellent application prospects.

Speaking of magnets, the coercive force is an important index for evaluating the superiority and inferiority of the Nd-Fe-B permanent magnet material magnet performance. Heavy rare earth elements Dy and Tb are important elements for improving coercive force, and can effectively improve the 2:14:1 phase magnetic crystal anisotropy constant, but their price is high. Therefore, in general, the coercive force is improved and the manufacturing cost of the magnet is lowered by immersion diffusion on the surface of the heavy rare earth elements Dy and Tb, but the concentration drop is relatively large as the heavy rare earth element moves from the surface to the inside, The diffusion depth is relatively shallow, and the performance improvement is limited.

In Chinese Invention Patent Application No. 201910183289.8, magnetron sputtering using one of low-temperature metals Cu, Al, Zn, Mg, Sn or one of low-temperature alloys CuAl, CuSn, CuZn, CuMg, SnZn, MgAl, MgCu, MgZn, AlMgZn, CuAlMg or depositing the low melting point pure metal or low melting point alloy on the magnet surface using vapor deposition, and depositing the heavy rare earth Dy or Tb on the magnet surface using vapor deposition or magnetron sputtering again. However, the method can only improve the coercive force of the magnet left and right by 37%, and further improvement cannot be realized.

It is an object of the present invention to provide a modified sintered neodymium-iron-boron magnet, wherein the material uses a low melting point alloy containing Pr, preferentially entering the magnet interior, to form a wider and longer diffusion passage, and again this Through the rapid diffusion path of the heavy rare earth element, the diffusion depth of the heavy rare earth element, its rate, and the coercive force can be further promoted, and the manufacturing cost is reduced.

A modified sintered neodymium-iron-boron magnet, manufactured by performing grain boundary diffusion with respect to a substrate, wherein the substrate is a sintered neodymium-iron-boron magnet, and the grain boundary diffusion source includes a first diffusion source and a second diffusion source Among them, the first diffusion source is a PrMx alloy, among which M is Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb, Mn, Co, Fe, At least one selected from Ti, Cr, Zr, Mo, and Ge, X means mass percentage, X is 8 to 90, excess is Pr and unavoidable impurities, and the second diffusion source is heavy rare earth Dy and/or is Tb.

In the grain boundary diffusion process of the present application, the first diffusion source diffuses first, and the second diffusion source diffuses later.

Optionally, a mass ratio of the substrate, the first diffusion source, and the second diffusion source is 100: 0.1 to 2: 0.1 to 1.

Optionally, in the modified sintered neodymium-iron-boron magnet, the grains are equiaxed, and the grain size is 2-20 μm.

Optionally, in the modified sintered neodymium-iron-boron magnet, wherein the grain boundary phase comprises a thin layer boundary phase located between two grains, in a region within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet, The thin grain boundary phase is distributed between the grains, the boundaries between the grains are clear, and the width of the thin grain boundary phase is between 50 and 500 nm.

Optionally, in the region within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet, the grains have a core-shell structure, and the shell layer thickness is 0.1-2.0 μm.

Second, there is provided a method for manufacturing a modified sintered neodymium-iron-boron magnet, comprising at least the following steps.

(1) An alloy film is prepared on the surface of a sintered neodymium-iron-boron magnet, of which the alloy film is PrMx, M is Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb , Mn, Co, Fe, Ti, Cr, Zr, Mo, at least one selected from Ge, X means mass percentage, X is 8 to 90, the excess is Pr and unavoidable impurities;

(2) preparing a heavy rare earth film on the surface of the alloy film obtained in step (1), wherein the heavy rare earth is Dy (TM=1412°C and/or Tb (TM=1356°C);

(3) Using the alloy film and the heavy rare-earth film as diffusion sources, grain boundary diffusion is carried out with respect to the sintered neodymium-iron-boron magnet to obtain a modified sintered neodymium-iron-boron magnet.

Preferably, M is at least one selected from Cu, Al, Zn, Ga, Fe, Ni, Co;

Optionally, the sintered neodymium-iron-boron magnet is a sintered neodymium-iron-boron magnet in a sintered state or in a tempered state.

Optionally, the melting point of the alloy film in step (1) is 400-700°C.

Optionally, the thickness of the alloy film in step (1) is 1 to 40 μm, preferably 5 to 20 μm.

Optionally, the specific method of manufacturing the alloy film in step (1) includes the following.

Under the condition that the degree of vacuum is ^{lower than 2Х10 -3} Pa, PrMx alloy is used as the target material, and the alloy film is deposited using the magnetron sputtering method.

Optionally, the thickness of the heavy rare earth film in step (2) is 1 to 20 μm, preferably 3 to 10 μm.

Optionally, the specific method of manufacturing the heavy rare earth membrane in step (2) includes the following contents.

Under a condition in which the degree of vacuum is ^{lower than 2Х10 -3} Pa, heavy rare earth film deposition is carried out using a magnetron sputtering method using heavy rare earth as a target material.

Optionally, the specific conditions of the grain boundary diffusion in step (3) include the following.

the degree of vacuum is lower than ^{3Х10 -3 Pa;}

The diffusion temperature is between 750°C and 1000°C;

The diffusion time is 0.5-24 h.

Furthermore, after the grain boundary diffusion proceeds, the tempering treatment is carried out at 430 ° C. to 640 ° C. for 0.5 to 10 h.

Preferably, the diffusion temperature is between 850°C and 950°C;

The diffusion time is 2–24 h.

Optionally, a mass ratio of the sintered neodymium-iron-boron magnet, the alloy film, and the heavy rare earth film is 100: 0.1-2: 0.1-1.

Among specific embodiments, a method for improving the magnet performance of a sintered neodymium-iron-boron magnet includes the following steps.

1) Clean the surface of the sintered neodymium-iron-boron magnet to ensure cleanliness and flatness of its upper and lower surfaces;

2) Under the condition that the degree of vacuum is ^{lower than 2Х10 -3} Pa, the thickness of the deposition layer of the low melting point alloy PrM containing Pr deposited on the magnet surface is 1-40 um, preferably 5-20 um;

3) Heavy rare earth Dy (TM=1412°C) or Tb (TM=1356°C) is deposited on the magnet surface, and the thickness of the deposition layer is 1-20um;

4) Put the treated magnet into the tempering furnace, vacuum it, and when the vacuum is ^{lower than 3Х10 -3} Pa, keep it warm at 850℃~950℃ for 2h~24h;

5) Insulate at 430℃~640℃ for 0.5~10h.

Optionally, the crystal grains of the modified sintered neodymium-iron-boron magnet are equiaxed, and the grain size is 2-20 um.

In the present application, the grain size means the maximum distance between two points in the crystal plane with the largest surface area among grains, that is, the length of the major grain axis.

Optionally, the grain boundary phase comprises a thin layer grain boundary phase located between two grains and a tripod type grain boundary phase located at several grain corners, in a region within 50 um from the diffusion surface of the sintered neodymium-iron-boron magnet, The thin grain boundary phase is uniformly distributed between the grains, the boundaries between the grains are clear, and the width of the thin grain boundary phase is between 50 and 500 nm.

Among them, in the present application, the diffusion surface of the sintered neodymium-iron-boron magnet means that it has an alloy film and a surface of a heavy rare earth film; The area within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet means the area of the vertical distance ≤ 50 μm of the diffusion surface; The width of the thin grain boundary phase means the shortest distance between adjacent grains.

Optionally, in the region within 50 um from the diffusion surface of the sintered neodymium-iron-boron magnet, the grains are core-shell structured grains, and the shell layer thickness is 0.1-2.0 um.

In the present application, the grain shell layer is a columnar epitaxial layer containing Tb and/or Dy.

Thirdly, in the present application, the modified sintered neodymium-iron-boron magnet manufactured by the manufacturing method as in any one of the above and the modified sintered neodymium-iron-boron magnet as in any one above are used for wind power generation, energy-saving home appliances and It provides applications in the field of renewable energy vehicles.

(1) The method of the present invention uses a low melting point alloy including Pr, preferentially enters the magnet, forms a wider and longer diffusion path, and uses this as a rapid diffusion path for heavy rare earth elements, It can further promote the diffusion depth and diffusion rate of rare earth elements, and improve the coercive force of the magnet.

(2) the method can lower the capacity of the heavy rare earth element, realize the improvement of the magnet coercive force, and significantly lower the cost;

(3) The method is simple in crafting, easy to realize, and has a wide application prospect.

1 is a scanning electron microscope view of the high coercive force magnet after grain boundary diffusion prepared in Example 1. FIG.
2 is a scanning electron microscope view of a sintered neodymium-iron-boron magnet before modification of Example 1. FIG.

In order for those skilled in the art to better understand the technical solution of the present invention, the following is a clear and complete description of the technical solution of the present invention in conjunction with the drawings of the present invention, and based on the embodiments of the present invention, those skilled in the art All other similar embodiments obtained under the premise of not doing creative labor should fall within the protection scope of the present invention. In addition, direction terms mentioned in the following examples, for example, 'top', 'bottom', 'left', 'right', etc. are only directions of the reference drawings, and therefore, the direction terms used are only used for explanation. It is not intended to limit the invention. All features disclosed in this specification, or all disclosed methods or steps in a process, can be combined in any way except for mutually exclusive features and/or steps. For all features disclosed in this specification (including all additional claims, abstracts and drawings), unless specifically stated otherwise, all other equivalent or alternative features for similar purposes may be substituted for them. That is, unless specifically stated, each feature is only one example of a series of equivalent or similar features.

In the present application, unless otherwise specified, all raw materials are general commercial products.

In the modified sintered neodymium-iron-boron magnet, it was manufactured by performing grain boundary diffusion with respect to a substrate, the substrate being a sintered neodymium-iron-boron magnet, and the grain boundary diffusion was composed of a first diffusion source and a second diffusion source, , among them, the first diffusion source is a PrMx alloy, among which M is Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb, Mn, Co, Fe, Ti, Cr , Zr, Mo, and Ge, X means mass percentage, X is 8 to 90, excess is Pr and unavoidable impurities, and the second diffusion source is heavy rare earth Dy and/or Tb.

In the grain boundary diffusion process of the present application, the first diffusion source diffuses first, and the second diffusion source diffuses later.

Optionally, a mass ratio of the substrate, the first diffusion source, and the second diffusion source is 100: 0.1 to 2: 0.1 to 1.

Optionally, in the modified sintered neodymium-iron-boron magnet, the grains are equiaxed, and the grain size is 2-20 μm.

Optionally, in the modified sintered neodymium-iron-boron magnet, wherein the grain boundary phase comprises a thin layer boundary phase located between two grains, in a region within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet, The thin grain boundary phase is distributed between the grains, the boundaries between the grains are clear, and the width of the thin grain boundary phase is between 50 and 500 mm.

Optionally, in the region within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet, the grains have a core-shell structure, and the shell layer thickness is 0.1-2.0 μm.

A method for manufacturing a modified sintered neodymium-iron-boron magnet, comprising at least the following steps.

(1) An alloy film is prepared on the surface of a sintered neodymium-iron-boron magnet, of which the alloy film is PrMx, M is Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb , Mn, Co, Fe, Ti, Cr, Zr, Mo, at least one selected from Ge, X means mass percentage, X is 8 to 90, the excess is Pr and unavoidable impurities;

(2) preparing a heavy rare earth film on the surface of the alloy film obtained in step (1), wherein the heavy rare earth is Dy (TM=1412°C and/or Tb (TM=1356°C);

(3) Using the alloy film and the heavy rare-earth film as diffusion sources, grain boundary diffusion is carried out with respect to the sintered neodymium-iron-boron magnet to obtain a modified sintered neodymium-iron-boron magnet.

Preferably, M is at least one selected from Cu, Al, Zn, Ga, Fe, Ni, Co;

Optionally, the sintered neodymium-iron-boron magnet is a sintered neodymium-iron-boron magnet in a sintered state or in a tempered state.

Optionally, the melting point of the alloy film in step (1) is 400 to 700°C.

Optionally, the thickness of the alloy film in step (1) is 1 to 40 μm, preferably 5 to 20 μm.

Optionally, the specific method of manufacturing the alloy film in step (1) includes the following.

Under the condition that the degree of vacuum is ^{lower than 2Х10 -3} Pa, PrMx alloy is used as the target material, and the alloy film is deposited using the magnetron sputtering method.

Optionally, the thickness of the heavy rare earth film in step (2) is 1 to 20 μm, preferably 3 to 10 μm.

Optionally, the specific method of manufacturing the heavy rare earth membrane in step (2) includes the following contents.

Under a condition in which the degree of vacuum is ^{lower than 2Х10 -3} Pa, heavy rare earth film deposition is carried out using a magnetron sputtering method using heavy rare earth as a target material.

Optionally, the specific conditions of the grain boundary diffusion in step (3) include the following.

the degree of vacuum is lower than ^{3Х10 -3 Pa;}

The diffusion temperature is between 750°C and 1000°C;

The diffusion time is 0.5-24 h.

Furthermore, after the grain boundary diffusion proceeds, the tempering treatment is carried out at 430 ° C. to 640 ° C. for 0.5 to 10 h.

Preferably, the diffusion temperature is between 850°C and 950°C;

The diffusion time is 2–24 h.

Optionally, a mass ratio of the sintered neodymium-iron-boron magnet, the alloy film, and the heavy rare earth film is 100: 0.1-2: 0.1-1.

Among specific embodiments, a method for improving the magnet performance of a sintered neodymium-iron-boron magnet includes the following steps.

1) Clean the surface of the sintered neodymium-iron-boron magnet to ensure cleanliness and flatness of its upper and lower surfaces;

2) Under the condition that the degree of vacuum is ^{lower than 2Х10 -3} Pa, the thickness of the deposition layer of the low melting point alloy PrM containing Pr deposited on the magnet surface is 1-40 um, preferably 5-20 um;

3) Heavy rare earth Dy (TM=1412°C) or Tb (TM=1356°C) is deposited on the magnet surface, and the thickness of the deposition layer is 1-20um;

4) Put the treated magnet into the tempering furnace, vacuum it, and when the vacuum is ^{lower than 3Х10 -3} Pa, keep it warm at 850℃~950℃ for 2h~24h;

5) Insulate at 430℃~640℃ for 0.5~10h.

Optionally, the crystal grains of the modified sintered neodymium-iron-boron magnet are equiaxed, and the grain size is 2-20 um.

In the present application, the grain size means the maximum distance between two points in the crystal plane with the largest surface area among grains, that is, the length of the major grain axis.

Optionally, the grain boundary phase comprises a thin layer grain boundary phase located between two grains and a tripod type grain boundary phase located at several grain corners, in a region within 50 um from the diffusion surface of the sintered neodymium-iron-boron magnet, The thin grain boundary phase is uniformly distributed between the grains, the boundaries between the grains are clear, and the width of the thin grain boundary phase is between 50 and 500 nm.

Among them, in the present application, the diffusion surface of the sintered neodymium-iron-boron magnet means that it has a surface of an alloy film and a heavy rare earth film; The area within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet means the area of the vertical distance ≤ 50 μm of the diffusion surface; The width of the thin grain boundary phase means the shortest distance between adjacent grains.

Optionally, in the region within 50 um from the diffusion surface of the sintered neodymium-iron-boron magnet, the grains are core-shell structured grains, and the shell layer thickness is 0.1-2.0 um.

In the present application, the grain shell layer is a columnar epitaxial layer containing Tb and/or Dy.

The modified sintered neodymium-iron-boron magnet manufactured by the manufacturing method as in any one of the preceding paragraphs and the modified sintered neodymium-iron-boron magnet as in any one above are used in wind power generation, energy-saving home appliances and renewable energy automobile fields. provides applications of

Example 1

(1) A sintered neodymium-iron-boron magnet whose composition is (PrNd) _27.67 Fe _68.71 B _0.97 Al _0.19 Co _0.82 Cu _0.16 Ga _0.18 Tb _0.64 (wt.%), i.e. 48H, is cut into pieces of 8*8*7 mm cut thinly with

(2) Clean the surface of the sintered neodymium-iron-boron magnet piece, and ensure the cleanliness and flatness of the upper and lower anode surfaces.

(3) When the vacuum degree is 1Х10 ^-3 Pa, using an alloy Pr ₉₂ Al ₈ (wt.%) with a melting point of 850℃ as the target material, magnetron sputtering is performed on the upper and lower anode surfaces of the sintered neodymium-iron-boron magnet pieces. Then, alloy films each having a thickness of 6 μm are formed on the surfaces of the upper and lower anodes.

(4) When the vacuum degree is 1Х10 ^-3 Pa, using magnetron sputtering technology to deposit heavy rare earth Tb on the surface of the alloy film, to obtain a heavy rare earth film with a layer thickness of 3 μm, at this time sintered neodymium-iron-boron magnet, alloy Pr ₉₂ Al _8, the mass ratio of heavy rare earth is 100: 0.3: 0.3;

(5) ^{Under the condition of vacuum degree 2Х10 -3} Pa, insulate at 920°C for 4h, and tempering at 500°C, and the tempering time is 2h. Obtain a high coercive force sintered neodymium-iron-boron magnet material, and record as material 1.

Example 2

(1) Cut a _{sintered neodymium-iron-boron magnet with the composition (PrNd) 27.67} Fe _68.71 B _0.97 Al _0.19 Co _0.82 Cu _0.16 Ga _0.18 Tb _0.64 (wt.%) thinly into pieces of 8*8*7 mm.

(2) Clean the surface of the sintered neodymium-iron-boron magnet piece, and ensure the cleanliness and flatness of the upper and lower anode surfaces.

(3) When the vacuum degree is 1Х10 ^-3 Pa, using an alloy Pr ₆₀ Ga ₄₀ (wt.%) with a melting point of 550℃ as the target material, magnetron sputtering is performed on the upper and lower anode surfaces of the sintered neodymium-iron-boron magnet pieces. Then, alloy films each having a thickness of 6 μm are formed on the surfaces of the upper and lower anodes.

(4) When the vacuum degree is 1Х10 ^-3 Pa, the heavy rare earth Tb is deposited on the surface of the alloy film by using magnetron sputtering technology, and a heavy rare earth film with a layer thickness of 3 μm is obtained.

(5) ^{Under the condition of vacuum degree 2Х10 -3} Pa, heat preservation at 900°C for 4h, and tempering at 520°C, tempering time is 2h. Obtain a high coercive force sintered neodymium-iron-boron magnet material, and record as material 2.

Examples 3-10

The manufacturing method is the same as in Example 1, the differences are as shown in Table 1, and the obtained materials are recorded as Material 3 to Material 10 in sequence.

Table of manufacturing conditions of each example Example Sintered Neodymium-Iron-Boron Magnets Alloy layer/thickness μm Heavy rare earth layer/thickness μm Diffusion temperature ℃/hour h tempering temperature ℃/hour h Example 1 48H Pr ₉₂ Al ₈ /6 Tb/3 920/4 500/2 Example 2 48H Pr ₆₀ Ga ₄₀ /6 Dy/3 900/4 520/2 Example 3 48H Pr ₇₀ Cu ₃₀ /10 Tb/4 920/4 500/2 Example 4 48H Pr ₆₀ Al ₂₀ Cu ₂₀ /10 Dy/4 900/4 520/2 Example 5 48H Pr ₆₀ Zn ₂₀ Cu ₂₀ /12 Tb/5 920/4 500/2 Example 6 48H Pr ₆₀ Ga ₂₀ Al ₂₀ /12 Dy/5 900/4 520/2 Example 7 48H Pr ₆₀ Fe ₂₀ Cu ₂₀ /14 Tb/6 920/4 500/2 Example 8 48H Pr ₆₀ Ni ₂₀ Al ₂₀ /14 Dy/6 900/4 520/2 Example 9 48H Pr ₆₀ Cu ₂₀ Zn ₂₀ /16 Tb/7 920/4 500/2 Example 10 48H Pr ₆₀ Cu ₁₅ Al ₁₅ Zn ₁₀ /16 Dy/7 900/4 520/2

Comparative Example 1

(1) Cut the sintered neodymium-iron-boron magnet (mutual 48H) into 8*8*7 mm pieces

(2) Clean the surface of the sintered neodymium-iron-boron magnet piece, and ensure the cleanliness and flatness of the upper and lower anode surfaces.

(3) When the vacuum degree is 1Х10 ^-3 Pa, using alloy Cu ₇₀ Zn ₃₀ as the target material, magnetron sputtering is performed on the upper and lower anode surfaces of the sintered neodymium-iron-boron magnet pieces, and the thickness is 16 μm on the upper and lower surfaces, respectively. A phosphorus alloy film is formed.

(4) when the vacuum degree is 1Х10 ^-3 Pa, depositing heavy rare earth Dy on the surface of the alloy film by using magnetron sputtering technology to obtain a heavy rare earth film with a layer thickness of 7 μm;

(5) ^{Under the condition of vacuum degree 2Х10 -3} Pa, insulate at 920°C for 4h, and tempering at 500°C, and the tempering time is 2h. Obtain a high coercive force sintered neodymium-iron-boron magnet material, and record as material 11.

Comparative Example 2

The manufacturing method of Comparative Example 1 is the same, with the only difference being that the alloy target material in step (2) is Cu ₇₀ Zn ₃₀ .

Morphological characterization is performed for each example.

Among them, the test method includes the following contents.

After the magnet is sliced along the elevation direction, microscopic tissue scanning is performed, and a known field emission scanning electron microscope SEM may be used as the scanning method. The observation method is to observe from the diffusion surface of the magnet toward the center, set an observation range of 80 μm (length)×40 μm (width) or more, to observe the microscopic shape of the material at different distances from the diffusion surface;

After the magnet is sliced along the elevation direction, microscopic tissue scanning is performed, and a known field emission scanning electron microscope SEM may be used as the scanning method. The observation method is to observe from the diffusion surface of the magnet toward the center, set an observation range of 80 μm (length) × 40 μm (width) or more, and directly determine the size of the image using SEM, thereby determining the grain size, the grain shell layer thickness and the thin grain boundary. Determine the width of the garment.

Material 1 provided in Example 1 will be described below as a typical representative, and all materials obtained in other examples have the same or similar shape.

1 is a slice electron micrograph within a range where the magnet is 50 μm from the diffusion surface. As shown in FIG. 1, the crystal grains in Material 1 are equiaxed, the crystal grain size is 2 to 20 μm, and the columnar phase of Material 1 is Nd ₂ Fe ₁₄ B, and the grain boundary phase of Material 1 includes a thin layer boundary phase located between two grains and a tripod type grain boundary phase located at several grain corners; 1 and 2, in comparison with the sintered neodymium-iron-boron magnet before modification, material 2 is in a region within 50 um from the diffusion surface of the sintered neodymium-iron-boron magnet, and the thin grain boundary phase is uniformly between the grains. distributed, the boundaries between the grains are clear, and the width of the thin grain boundary phase is between 50 and 500 nm; Among the regions within 50 um from the diffusion surface of the sintered neodymium-iron-boron magnet, the grains are those of the core-shell structure, and the shell layer thickness is 0.1-2.0 um.

A performance test is performed for each Example and Comparative Example.

Using the NIM-500C magnetic measuring instrument, measure the residual magnetism, coercive force, and magnetic energy product of each material under a room temperature environment, and the test results are shown in Table 2.

List of parameters of magnet performance of materials obtained in each Example and Comparative Example Example Micromagnetic (T) Coercive force (kOe) Magnetic Energetic (MGOe) Example 1 1.39 25.6 46.8 Example 2 1.40 23.5 47.3 Example 3 1.41 25.9 47.3 Example 4 1.39 23.8 47.6 Example 5 1.38 26.6 48.0 Example 6 1.38 24.1 48.1 Example 7 1.39 27.2 47.5 Example 8 1.37 24.3 46.9 Example 9 1.37 28.0 46.4 Example 10 1.36 24.8 46.5 Comparative Example 1 1.37 23.4 46.2 Comparative Example 2 1.36 23.2 46.4 Unmodified Neodymium-Iron-Boron Magnets 1.41 18.2 48.5

As can be seen from Table 2, the material provided in the examples of the present application improved the magnet's coercive force by 29% at 18.2 kOe before grain boundary diffusion, and the coercive force was hardly lowered. In particular, the material 9 provided in Example 9 improved the coercive force by nearly 54%; In contrast, Comparative Examples 1 and 2 improved the coercive force by only 28.5% under similar conditions to those of Example 9.

The present invention has been described in detail above, and the above content is only a preferred embodiment of the present invention, and cannot limit the scope of the present invention, that is, all equivalent changes and modifications made in the scope of the present application are of the present invention. fall within the scope

Claims (16)

A modified sintered neodymium-iron-boron magnet comprising:
It is manufactured by performing grain boundary diffusion with respect to a substrate, wherein the substrate is a sintered neodymium-iron-boron magnet, and the grain boundary diffusion source is composed of a first diffusion source and a second diffusion source, among which, the first diffusion The circle is a PrMx alloy, among which M is selected from Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb, Mn, Co, Fe, Ti, Cr, Zr, Mo, Ge Modified sintered neodymium-iron, characterized in that X means mass percentage, X is 8 to 90, excess is Pr and unavoidable impurities, and the second diffusion source is heavy rare earth Dy and/or Tb - Boron magnets.
According to claim 1,
A modified sintered neodymium-iron-boron magnet, characterized in that the mass ratio of the base material, the first diffusion source, and the second diffusion source is 100: 0.1 to 2: 0.1 to 1.
3. The method of claim 2,
The modified sintered neodymium-iron-boron magnet, characterized in that the grains are equiaxed, and the grain size is 2-20 μm.
3. The method of claim 2,
The grain boundary phase includes a thin grain boundary phase located between two grains, and in a region within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet, the thin grain boundary phase is distributed between the grains, and the boundary between the grains is clear. and a modified sintered neodymium-iron-boron magnet, characterized in that the width of the thin-layer grain boundary phase is between 50 and 500 nm.
5. The method of claim 4,
A modified sintered neodymium-iron-boron magnet characterized in that, in an area within 50 μm from the diffusion surface of the sintered neodymium-iron-boron magnet, the grains have a core-shell structure, and the shell layer thickness is 0.1-2.0 μm.
A method for manufacturing a modified sintered neodymium-iron-boron magnet, comprising:
It comprises at least the following steps,
(1) An alloy film is prepared on the surface of a sintered neodymium-iron-boron magnet, of which the alloy film is PrMx, M is Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb , Mn, Co, Fe, Ti, Cr, Zr, Mo, at least one selected from Ge, X means mass percentage, X is 8 to 90, the excess is Pr and unavoidable impurities;
(2) preparing a heavy rare earth film on the surface of the alloy film obtained in step (1), wherein the heavy rare earth is Dy (TM=1412°C and/or Tb (TM=1356°C);
(3) modified sintered neodymium-iron magnets are obtained by using the alloy film and the heavy rare earth film as diffusion sources and performing grain boundary diffusion with respect to the sintered neodymium-iron-boron magnet - Method of manufacturing boron magnets.
7. The method of claim 6,
Method of manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that the melting point of the alloy film in step (1) is 400 ~ 700 ℃.
7. The method of claim 6,
The method of manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that the thickness of the alloy film in step (1) is 1-40 μm.
7. The method of claim 6,
The specific method for manufacturing the alloy film of step (1) includes the following,
A method for manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that, under a condition in which the degree of vacuum is ^{lower than 2Х10 -3 Pa, using PrMx alloy as a target material, and depositing the alloy film using a magnetron sputtering method.}
7. The method of claim 6,
The method for manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that the thickness of the heavy rare earth film in step (2) is 1-20 μm.
7. The method of claim 6,
The specific method for manufacturing the heavy rare earth membrane in step (2) includes the following,
A method for manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that heavy rare earth film deposition is carried out using a magnetron sputtering method using a heavy rare earth material as a target material under a condition in which the degree of vacuum is ^{lower than 2Х10 -3 Pa.}
7. The method of claim 6,
The specific conditions for the grain boundary diffusion in step (3) include the following,
the degree of vacuum is lower than ^{3Х10 -3 Pa;}
The diffusion temperature is between 750°C and 1000°C;
A method of manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that the diffusion time is 0.5 to 24 h.
7. The method of claim 6,
A method of manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that after grain boundary diffusion is performed, a tempering treatment is performed at 430°C to 640°C for 0.5 to 10 h.
7. The method of claim 6,
The diffusion temperature is 850°C to 950°C;
A method for manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that the diffusion time is 2 to 24 h.
7. The method of claim 6,
The method for manufacturing a modified sintered neodymium-iron-boron magnet, characterized in that the mass ratio of the sintered neodymium-iron-boron magnet, the alloy film, and the heavy rare earth film is 100: 0.5 to 1: 0.2 to 0.6.
A modified sintered neodymium-iron-boron magnet as in any one of claims 1 to 6, a modified sintered neodymium-iron-boron magnet as in any one of claims 7 to 16, and a modified manufactured method A sintered neodymium-iron-boron magnet comprising:
At least one has applications in wind power generation, energy-saving home appliances and renewable energy vehicles.

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